Auxin and hydrogen peroxide (H2O2) interaction differentially regulate seedling growth, Na+/K+ ratio and H2S homeostasis accompanying NaCl stress in etiolated sunflower (Helianthus annuus L. cv. Microgreen) seedling roots and cotyledons
Soumya Mukherjee, Rewaj Subba, Fahad Mohammed Alzuaibr, Piyush Mathur
Abstract
Although H 2 S has been reported to modulate auxin and H 2 O 2 signaling during abiotic stress, no reports decipher the interactive roles of exogenous auxin and H 2 O 2 on the regulation of endogenous H 2 S homeostasis . In the present work, auxin (IAA) and hydrogen peroxide (H 2 O 2 ) interaction appear to be crucial in regulating Na + /K + homeostasis , recovery in seedling growth and H 2 S accumulation in NaCl-stressed sunflower seedlings. Interestingly, impairment in endogenous IAA transport (TIBA application) also impacts H 2 S accumulation in the roots and cotyledons . IAA supplementation is effective in reducing Na + /K + ratio and electrolytic leakage in roots, which reverses in the presence of TIBA (polar auxin transport inhibitor) application. IAA and H 2 O 2 -mediated modulation of H 2 S content corroborates with l -DES activity in seedling roots and cotyledons. In contrast to cotyledons, roots exhibited a reduction in H 2 S content in the presence of treatments (IAA and H 2 O 2 ). H 2 O 2 supplementation seems to partially circumvent the changes caused by the disruption of auxin transport. Thus, we hypothesize that auxin might imply H 2 O 2 as a crucial signaling component in the regulation of H 2 S levels in sunflower tissues. To sum up, IAA and H 2 O 2 interaction regulates root growth, LR proliferation, Na + /K + ratio, and H 2 S metabolism in sunflower seedling roots.